6-(Substituted phenoxy)-2-di-(substituted phenoxy)methyl pyridines

ABSTRACT

Compounds are prepared corresponding to the formula ##STR1## wherein Y represents chloro or R&#39;; R represents ##STR2## wherein X independently represents alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms, alkylthio of 1 to 4 carbon atoms, alkyl sulfonyl of 1 to 4 carbon atoms, trifluoromethyl, chloro, fluoro or bromo; n represents an integer of 0 to 2 or X n  represents 3,4-methylenedioxy and R&#39; represents R with the proviso that R and R&#39; can be the same or different. The compounds are useful as intermediates for the preparation of insecticidal substituted pyridine methyl esters of cyclopropane carboxylic acids.

BACKGROUND OF THE INVENTION

Substituted phenoxy pyridine methyl esters of cyclopropane carboxylicacids are taught in U.S. Pat. No. 4,163,787 issued Aug. 7, 1979. Thesecompounds are taught to be useful in the kill and control of variousinsect pest. These compounds are taught as being prepared by thereaction of an appropriate substituted phenoxy pyridine methanol with anappropriate 2,2-dimethyl-3-(2,2-dihaloethenyl)cyclopropane carboxylicacid halide.

While the above procedure is efficient in the preparation of the desiredcompounds, the cost of the substituted phenoxy pyridine methanols usedin that procedure has made the so prepared desired compounds veryexpensive and less attractive for exploitation.

The substituted phenoxy pyridine methanols are prepared from thecorresponding picolinaldehyde which in turn is made from thecorresponding methyl picolinate. It is the cost of the above aldehydeand picolinate intermediates which makes the cost of the methanols sohigh. New processes for preparing these materials are being sought.

SUMMARY OF THE INVENTION

The present invention is directed to compounds corresponding to theformula ##STR3## wherein Y represents chloro or R'; R represents##STR4## wherein X independently represents alkyl of 1 to 4 carbonatoms, alkoxy of 1 to 4 carbon atoms, alkylthio of 1 to 4 carbon atoms,alkyl sulfonyl of 1 to 4 carbon atoms, trifluoromethyl, chloro, fluoroor bromo; n represents an integer of 0 to 2 or X_(n) represents3,4-methylenedioxy and R' represents R with the proviso that R and R'can be the same or different; and to a method for making such compounds.

The present invention is also directed to the conversion of the aboveintermediate compounds to the corresponding picolinaldehydes, or in theuse of those compounds wherein Y is chloro as intermediates to prepareadditional intermediate compounds for conversion into the correspondingpicolinaldehydes. The so prepared picolinaldehydes can in turn beconverted to substituted phenoxy pyridine methanols. These lattercompounds can then be reacted with an appropriate2,2-dimethyl-3-(2,2-dihaloethenyl)cyclopropane carboxylic acid halide,as taught in U.S. Pat. No. 4,163,787, to prepare insecticidalsubstituted pyridine methyl esters of cyclopropane carboxylic acids.

The 6-(chloro or substituted phenoxy)-2-di-(substituted phenoxy)methylpyridines of the present invention are either solids or liquids whichare only slightly soluble in water and usually are moderately to highlysoluble in common organic solvents.

The compounds of the present invention can be prepared by the reactionof one mole of 2-chloro-6-(dichloromethyl)pyridine with from about 1 toabout 3 moles of an alkali metal salt of at least one substituted phenolin the presence of a solvent.

Those compounds of the present invention wherein R and R' are the samecan be prepared by the reaction of one mole of2-chloro-6-(dichloromethyl)pyridine with 3 moles of an alkali metal saltof the appropriate substituted phenol in the presence of a solvent. Thisreaction scheme is as follows: ##STR5## wherein X and n are ashereinbefore defined and M is sodium, potassium, lithium or cesium.

In carrying out this reaction, the pyridine reactant and the salt of thephenol are mixed together in the presence of a solvent and heated to atemperature of from about 100° to about 200° C. and stirred for fromabout 2 to about 24 hours. Thereafter, the reaction product is cooled,diluted with water and extracted with a solvent such as for example,1,1,1-trichloroethane, methylene chloride, chloroform, ethyl acetate orethyl ether. The solvent extract is water washed, dried and concentratedunder reduced pressure and if desired, purified by distillation or otherconventional methods.

The reaction consumes the reactants in stoichiometric proportions, i.e.one molar equivalent of the pyridine reactant to 3 molar equivalents ofthe phenol reactant. However, due to the nature of the reaction, it ispreferred that a 5 to 25 percent excess of the phenol reactant beemployed.

While the above procedure shows the use of an already prepared alkalimetal salt of the phenol, this salt can be prepared in situ. In such aprocedure, the pyridine reactant, an appropriate substituted methoxyphenol and an alkali metal hydroxide are mixed together with the solventand then heated as set forth hereinabove. The alkali metal hydroxide isemployed in a molar amount equal to that employed for the phenolreactant.

Representative solvents for use in carrying out this reaction includedimethyl sulfoxide, dimethyl formamide, N-methyl-2-pyrrolidone, tolueneand xylene.

Those compounds of the present invention wherein Y is chloro can beprepared by the reaction of one mole of2-chloro-6-(dichloromethyl)pyridine with 2 moles of an alkali metal saltof the appropriate substituted phenol in the presence of a solvent. Thisreaction scheme is as follows: ##STR6## wherein X, n and M are ashereinbefore defined.

The reaction and the separation of the desired product can be carriedout as set forth above for those compounds wherein R and R' are thesame.

Those compounds of the present invention wherein R and R' are differentcan be prepared by the reaction of one mole of a2-chloro-6-((disubstituted phenoxy)methyl)pyridine, prepared as above,with one mole of an alkali metal salt of the appropriate substitutedphenol in the presence of a solvent. This reaction scheme is as follows:##STR7## wherein X, n and M are as hereinbefore defined.

The reaction and the separation of the desired product can be carriedout as set forth above for those compounds wherein R and Y are the sameor wherein R' is chloro.

The 6-(substituted phenoxy)-2-di-(substituted phenoxy)methyl pyridineproduct can be hydrolyzed to the corresponding 6-(substitutedphenoxy)picolinaldehyde by acid hydrolysis with an inorganic or organicacid and, if desired, in the presence of a solvent.

In carrying out the hydrolysis step, one mole of the 6-(substitutedphenoxy)-2-di-(substituted phenoxy)methyl pyridine is mixed with anexcess of an inorganic or organic acid such as, for example, sulfuricacid, dilute hydrochloric acid or acetic acid. The reaction can beconducted, if desired, in the presence of a solvent or reaction mediumsuch as, for example, 1,4-dioxane, monoglyme or water. The mixture isheated to a temperature of from about 60° to about 150° C. for fromabout 10 minutes to 12 hours or more. The reaction product is cooled,diluted with water and extracted with a solvent such as, for exampleethyl ether, methylene chloride or chloroform. The desired product canbe recovered from the solvent extract by conventional recoverytechniques which include, for example, water washing, washing withdiluted sodium hydroxide and a saturated salt solution, drying andsolvent removal under reduced pressure.

DESCRIPTION OF SOME PREFERRED EMBODIMENTS

The following examples further illustrate the present invention.

EXAMPLE I 2-Chloro-6-(diphenoxymethyl)pyridine ##STR8##

A mixture of 25 grams (g) (0.13 mole (m)) of2-chloro-6-(dichloromethyl)pyridine, 29.91 g (0.32 m) of phenol and17.84 g (0.32 m) of potassium hydroxide in 100 milliliters (ml) ofdimethylsulfoxide was heated, with stirring, for 6 hours at 70° C. Thereaction mixture was cooled, diluted with water and extracted with1,1,1-trichloroethane. The extract was washed with water, dried overanhydrous magnesium sulfate and concentrated under reduced pressure. Theconcentrate was subjected to Kugelrohr distillation and 27.3 g of ayellow viscous liquid was recovered. This liquid was determined to bethe desired 2-chloro-6-(diphenoxymethyl)pyridine by its nuclearmagnectic resonance spectra and its elemental analysis. The productboiled at 150° C. at 0.1 millimeter of mercury (mm) and had a refractiveindex of n_(D) ²⁵ =1.5991. The elemental analysis showed the product tohave carbon, hydrogen and nitrogen contents of 68.63, 4.40 and 4.49percent, respectively, as compared with the theoretical contents of69.34, 4.49 and 4.49 percent, respectively, as calculated for the abovenamed compound.

By following the preparative procedure as outlined in the above example,the following compounds set forth below in TABLE I can be prepared.

                                      TABLE I                                     __________________________________________________________________________     ##STR9##                                                                              Analysis                                                                      Calculated                                                                             Found                                                       X.sub.n  C  H  N  C  H  N  Physical Property*                                 __________________________________________________________________________    4-Cl     56.77                                                                            3.15                                                                             3.68                                                                             56.44                                                                            3.14                                                                             3.72                                                                              ##STR10##                                         2-Cl                                                                          3-Cl                                                                          2-Cl; 4-Br                                                                    2-Br                                                                          3-OCH.sub.3                                                                            64.60                                                                            4.85                                                                             3.77                                                                             64.28                                                                            4.98                                                                             3.47                                                                              ##STR11##                                         4-Br     46.01                                                                            2.56                                                                             2.98                                                                             45.31                                                                            2.63                                                                             2.85                                                                             M.P. = 75°-78° C.                    2-CH.sub.3                                                                    4-CH.sub.3                                                                             70.69                                                                            5.30                                                                             4.12                                                                             69.95                                                                            5.35                                                                             4.07                                                                              ##STR12##                                         4-C.sub.4 H.sub.9                                                             2-Cl; 4-CF.sub.3                                                              2-CF.sub.3                                                                    3-CF.sub. 3                                                                            53.63                                                                            2.68                                                                             3.13                                                                             53.41                                                                            2.73                                                                             3.17                                                                              ##STR13##                                         3-F      62.16                                                                            3.45                                                                             4.03                                                                             61.45                                                                            3.62                                                                             4.03                                                                              ##STR14##                                         4-F      62.16                                                                            3.45                                                                             4.03                                                                             61.98                                                                            3.54                                                                             4.07                                                                              ##STR15##                                         4-SCH.sub.3                                                                            59.48                                                                            4.46                                                                             3.47                                                                             59.11                                                                            4.26                                                                             3.85                                                  3,5-(SCH.sub.3).sub.2                                                         2-OC.sub.4 H.sub.9                                                            2,4-OC.sub.4 H.sub.9                                                          4-OCH.sub.3                                                                            64.60                                                                            4.85                                                                             3.77                                                                             64.38                                                                            4.99                                                                             3.56                                                                              ##STR16##                                         4-SC.sub.4 H.sub.9                                                            4-SO.sub.2 CH.sub.3                                                           4-SO.sub.2 C.sub.4 H.sub.9                                                     ##STR17##                                                                    3,5-(CF.sub.3).sub.2                                                          __________________________________________________________________________     *M.P. = Melting Point;                                                        ##STR18##                                                                

By following the preparative procedures as outlined above using ˜onemole of the appropriate phenol or substituted phenol and one mole of theappropriate 2-chloro-6-(substituted phenoxy)pyridine, the followingcompounds can be prepared.

    ______________________________________                                         ##STR19##                                                                    R                 R'                                                           ##STR20##                                                                                       ##STR21##                                                  X.sub.n           X.sub.n                                                     ______________________________________                                        4-Cl              2-Cl                                                        2-Cl              2-Cl; 4-Br                                                  3-Cl              4-C.sub.4 H.sub.9                                           2-Cl; 4-Br        2-Cl; 4-CF.sub.3                                            2-Br              2-Cl                                                        4-Br              3-Cl                                                        2-CH.sub.3        4-C.sub.4 H.sub.9                                           4-CH.sub.3        2-CH.sub.3                                                  4-C.sub.4 H.sub.9 2-F                                                         2-Cl; 4-CF.sub.3  2-Cl                                                        2-CF.sub.3        2-Cl                                                        3-CF.sub.3        2-CF.sub.3                                                  3-F               4-F                                                         4-F               3-F                                                         4-SCH.sub.3       2-Cl                                                        3,5-(SCH.sub.3).sub.2                                                                           4-SCH                                                       2-OC.sub.4 H.sub.9                                                                              2-OCH.sub.3                                                 2,4-OC.sub.4 H.sub.9                                                                            2-OCH.sub.3                                                 2-OCH.sub.3       4-OCH.sub.3                                                 3-OCH.sub.3       4-SCH.sub.3                                                 4-SC.sub.4 H.sub.9                                                                              2-Cl                                                        4-SO.sub.2 CH.sub.3                                                                             2-Cl                                                        4-SO.sub.2 C.sub.4 H.sub.9                                                                      2-OC.sub.4 H.sub.9                                           ##STR22##        2-Cl                                                        3,5-(CF.sub.3).sub.2                                                                            2-CF.sub.3                                                  ______________________________________                                    

EXAMPLE II 2-[Bis-(4-methoxyphenoxy)methyl]-6-(4-methoxyphenoxy)pyridine##STR23##

A mixture of 15.04 grams (g) (0.076 mole (m)) of2-dichloromethyl-6-chloropyridine, 39.50 g (0.32 m) of p-methoxyphenoland 18.14 g (0.32 m) of potassium hydroxide in 100 milliliters (ml) ofdimethylsulfoxide was heated, with stirring, for 72 hours. The resultingmixture was cooled to 25° C., diluted with water and extracted with1,1,1-trichloroethane. The extract was washed with water, dried overanhydrous magnesium sulfate and concentrated under reduced pressure. Theconcentrate was subjected to Kugelrohr distillation removing asimpurities any material boiling up to 200° C. at 0.05-1 millimeter ofmercury (mm). The2-[bis-(4-methoxyphenoxy)methyl]-6-(4-methoxyphenoxy)pyridine productwas removed as the residue of the distillation and was a brown thickoil. The product was obtained in a yield of 25.3 g and upon analysis,was found to have carbon, hydrogen and nitrogen contents of 70.80, 5.37and 3.09 percent, respectively, as compared with the theoreticalcontents of 70.59, 5.45 and 3.05 percent, respectively, as calculatedfor the above named compound.

By following the preparative procedure as outlined in the above example,the following compounds set forth below in Table II can be prepared.

                                      TABLE II                                    __________________________________________________________________________     ##STR24##                                                                             Analysis                                                                      Calculated                                                                             Found                                                       X.sub.n  C  H  N  C  H  N  Physical Property*                                 __________________________________________________________________________      --     78.03                                                                            5.18                                                                             3.79                                                                             77.96                                                                            5.30                                                                             3.83                                                                             M.P. = 85°-86.5° C.                  4-Cl     60.95                                                                            3.39                                                                             2.96                                                                             60.41                                                                            3.44                                                                             2.91                                                  2-Cl                                                                          3-Cl                                                                                                      ##STR25##                                         2-Cl; 4-Br                                                                    2-Br                                                                          4-Br     47.52                                                                            2.64                                                                             2.31                                                                             47.04                                                                            2.71                                                                             2.22                                                                             M.P. = 114°-116° C.                  2-CH.sub.3                                                                    4-CH.sub.3                                                                             78.83                                                                            6.08                                                                             3.41                                                                             78.17                                                                            6.11                                                                             3.30                                                                              ##STR26##                                         4-C.sub. 4 H.sub.9                                                            2-Cl; 4-CF.sub.3                                                              2-CF.sub.3                                                                    3-CF.sub.3                                                                             56.54                                                                            2.79                                                                             2.44                                                                             56.22                                                                            2.81                                                                             2.39                                                                              ##STR27##                                         3-F      68.09                                                                            3.78                                                                             3.31                                                                             67.84                                                                            3.88                                                                             3.22                                                                              ##STR28##                                         4-F                                                                           4-SCH.sub.3                                                                   3,5-(SCH.sub.3).sub.2                                                         2-OC.sub.4 H.sub.9                                                            2,4-OC.sub.4 H.sub.9                                                          2-OCH.sub.3                                                                   4-SC.sub.4 H.sub.9                                                            4-SO.sub.2 CH.sub.3                                                           4-SO.sub.2 C.sub.4 H.sub.9                                                     ##STR29##                                                                             64.67                                                                            3.79                                                                             2.79                                                                             63.13                                                                            3.81                                                                             2.62                                                  3,5-(CF.sub.3).sub.2                                                          __________________________________________________________________________     *M.P. = Melting Point;                                                        ##STR30##                                                                

EXAMPLE III 6-(3-Fluorophenoxy)picolinaldehyde ##STR31##

A solution of 2.5 g (0.0059 m) of2-[bis-(3-fluorophenoxy)methyl]-6-(3-fluorophenoxy)pyridine and 20 ml of80 percent acetic acid was heated, with stirring, at 150° C. overnight.The reaction mixture was cooled, diluted with water and extracted withmethylene chloride. The extract was washed with water and concentratedunder reduced pressure. The desired 6-(3-fluorophenoxy)picolinaldehydewhich melted at 42°-43° C.

EXAMPLE IV 6-(phenoxy)-picolinaldehyde ##STR32##

To a solution of 0.5 g of 2-[bis-(phenoxy)methyl]-6-(phenoxy)pyridine in15 ml of 1,4-dioxane was added dropwise, 5 percent sulfuric acid untilthe mixture just became turbid. The mixture was heated over a steam bathat 80°-90° C. for about 10 minutes. The reaction mixture was poured into20 ml of water, producing a yellowish emulsion and then extracted with50 ml of ethyl ether. The extract was washed with 50 ml of a 5 percentaqueous sodium hydroxide solution and thrice with 50 ml portions ofwater and then with 50 ml of a saturated sodium chloride solution. Theextract was then dried over sodium sulfate and the solvent removed byevaporation under reduced pressure. The residue was a yellow-orange oilwhich solidified partially on cooling to yield 0.25 g of the desiredproduct. The product was confirmed by Infrared and Nuclear Magneticresonance analysis.

By following the preparative procedures as outlined in the aboveExamples, the following compounds can be prepared.

    ______________________________________                                         ##STR33##                                                                               X.sub.n                                                            ______________________________________                                                   2-Cl                                                                          3-Cl                                                                          4-Cl                                                                          2-Cl; 4-Br                                                                    2-Br                                                                          4-Br                                                                          3-F                                                                           4-F                                                                           2-CH.sub.3                                                                    4-CH.sub.3                                                                    4-C.sub.4 H.sub.9                                                             2-Cl; 4-CF.sub.3                                                              2-CF.sub.3                                                                    3-CF.sub.3                                                                    4-SCH.sub.3                                                                   3,5-(SCH.sub.3).sub.2                                                         2-OC.sub.4 H.sub.9                                                            2,4-OC.sub.4 H.sub.9                                                          2-OCH.sub.3                                                                   4-SC.sub.4 H.sub.9                                                            4-SO.sub.2 CH.sub.3                                                           4-SO.sub.2 C.sub.4 H.sub.9                                                     ##STR34##                                                                    3,5-(CF.sub.3).sub.2                                               ______________________________________                                    

Preparation of Starting Materials

The 2-(chloro-6-(dichloromethyl)pyridines employed as starting materialsin the present invention are known compounds which can be prepared astaught in U.S. Pat. No. 3,687,827.

What is claimed is:
 1. A compound corresponding to the formula ##STR35##wherein Y represents R'; R represents ##STR36## wherein X independentlyrepresents alkyl of 1 to 4 carbon atoms, alkoxy of 1 to 4 carbon atoms,alkylthio of 1 to 4 carbon atoms, alkyl sulfonyl of 1 to 4 carbon atoms,trifluoromethyl, chloro, fluoro or bromo; n represents an integer of 0to 2 or X_(n) represents 3,4-methylenedioxy and R' represents R with theproviso that R and R' can be the same or different.
 2. The compound ofclaim 1 in which Y is R' and R' represents R.
 3. The compound of claim 1in which R and R' are different.
 4. The compound of claim 1 in which Rand R' are the same.
 5. The compound of claim 4 which is2-[bis-(phenoxy)methyl]-6-(phenoxy)pyridine.
 6. The compound of claim 4which is 2-[bis-(-4-methylphenoxy)methyl]-6-(4-methylphenoxy)pyridine.7. The compound of claim 4 which is2-[bis-(-3-chlorophenoxy)methyl]-6-(3-chlorophenoxy)pyridine.
 8. Thecompound of claim 4 which is2-[bis-(-4-chlorophenoxy)methyl]-6-(4-chlorophenoxy)pyridine.
 9. Thecompound of claim 4 which is2-[bis-(-3-fluorophenoxy)methyl]-6-(3-fluorophenoxy)pyridine.
 10. Thecompound of claim 4 which is2-[bis-(-4-fluorophenoxy)methyl]-6-(4-fluorophenoxy)pyridine.